This invention relates to color image transfer techniques for distributing or transferring a color image and an object for preparing a color image over a network and in particular to an image transfer apparatus, an image transmitter, a profile information transmitter, an image receiver/reproducer, a storage medium, an image receiver, a program transmitter, and an image color correction apparatus which enable a receiving party to display an image with original image colors held.
As information processing and communication technologies have become advanced, various techniques for connecting various devices for handling color image information, such as scanners, facsimiles, and color printers, and transferring color images between the devices have been proposed.
By the way, the transferred color image is reproduced by reproduction means such as a display device of the receiving party. At the time, the characteristics of the image input device at the transmitting party (for example, a scanner) do not necessarily match those of the reproduction means at the receiving party (for example, a color printer), thus it becomes necessary to execute color conversion in the color image transfer process.
Disclosed as one of the color conversion techniques, for example, in the Unexamined Japanese Patent Application Publication Nos. Hei 7-203175 and 7-312694 is a technique wherein the transmitting party has a color conversion function and the receiving party transfers profile information to the transmitting party, which then executes color conversion and transmits the resultant image to the receiving party, which will be hereinafter referred to as first prior art. The profile information is information defining the characteristics of a color space used to describe colors used in color image information; generally, color spaces defined based on perception of human beings, such as CIE XYZ and CIE L*a*b*, and information describing the mathematical relationship between the color spaces of color image information are used. In addition to the first prior art, a technique wherein the receiving party has a color conversion function and the transmitting party transfer profile information and an image to the receiving party, which then executes color conversion, which will be hereinafter referred to as second prior art, is disclosed in the Unexamined Japanese Patent Application Publication No. Hei 7-312694.
By the way, to apply the conventional techniques described above to an image transfer apparatus using a large-scale network environment such as the Internet, an undesired situation occurs on efficiency of communication lines or administration of the system. That is, if the first prior art is applied, the color conversion function at the transmitting party must deal with color conversion requests from a large number of receivers. Thus, the transmitting party requires a large processing capability and if it has an insufficient processing capability, processing takes time. On the other hand, if the second prior art is applied, when the receiving party receives images from a number of transmitters, even if the received images have the same color space, profile information needs to be transmitted each time the transmitting party changes. Thus, fruitless communication becomes necessary and efficient use of the communication line capacity cannot be made. If either of the first and second prior arts is applied, it becomes necessary to transfer profile information between the transmitting and receiving parties each time one image transfer is executed. Thus, it cannot be avoided to bear the communication costs to transfer the profile information.